Razorbill - 1994

Breeding resident and passage migrant

Breeding distribution seems to have changed little since the time of Mathew (1894). Assessing numbers, though, is even more problematical

than for Guillemot, for a large proportion breed in rock crevices where they are not readily visible.

Changes in the fortunes of the Razorbill have been very similar to those of Guillemot. Lockley et al. (1949) noted a decrease in numbers following the second World War, which they attributed to the effects of oil pollution. The population continued to decrease thereafter, with numbers on Skomer, for example, falling from about 2,100 pairs in 1963 to about 1,600 by 1974. In addition to oil pollution, Razorbills in the Irish Sea area were also casualties of toxic residue build-up (Saunders 1976). The Operation Seafarer survey of 1969 found about 3,000 breeding pairs in Pembrokeshire, about 50% of which were at Skomer.

Despite the Irish Sea seabird wreck of 1969 and oiling incidents such as those involving the Christos Bitas and Bridgeness, Razorbills began increasing again in the late 1970s and 1980s. The Seabird Register survey of 1985-1987 found about 6,600 occupied sites in Pembrokeshire, the major colonies being at Skomer (3,869), Ramsey (927), Skokholm (702), Elegug Stacks, Flimston (393), Needle Rock, Fishguard (266), Stackpole Head (138) and St Margaret's Island (154).

Flightless young and moulting adult Razorbills gather off Strumble Head with Guillemots during August and September. Ringing has shown that some Razorbills stay in home waters throughout the year, while others, particularly first year birds, wander to Ireland, Scotland, the North Sea (as far north as Norway), the English Channel, all the way down the Bay of Biscay and into the Mediterranean.

Large numbers pass southwards out of the Irish Sea between late September and early December, often mixed with Guillemots but normally greatly outnumbered by them, though a remarkable 20,000 birds were estimated to have passed Strumble Head on 25 October 1992.

Fieldwork 1984-88 (based on 478 tetrads)

Red = breeding confirmed = 24

Total tetrads in which registered = 24 (5%)

Donovan J.W. & Rees G.H (1994), Birds of Pembrokeshire